Bi-wiring and Damping Factor

[Hardhead]

This is intended to be a legitimate question about wire. I'm not asking if wire makes a difference or if one brand is better than another, so let's not go there.

Given a generic cable, I'm aware that an amplifier's damping factor decreases as the cable gets smaller and its resistance increases. I'm also aware that one way to increase the effective size of the cable without actually getting bigger cable is to use more than one cable for each line. My question is: Does bi-wiring (not bi-amping) effectively double the size of the original cable and increase the damping factor the same way as doubling the cable or does it cause the amplifier to "see" effectively two loudspeakers (woofer and tweeter/midrange) instead, thereby having no effect on increasing the cable size?

Thanks in advance for your help. Text

[WMcD]

It is a good question. I'm with mde.

Gil

[djk]

Against my better judgement I am going to say something here.Damping factor is a meaningless specification.I own several McIntosh amplifiers with damping factors that barely make it out of the single digit range.The autoformer is responsible for that.Stock the amplifiers sound slow and thick.Must be the damping factor, right? How come adding a couple of 47µF power supply bypass capacitors made the amps have jackhammer bass? Much tighter than an Adcom with a damping factor over ten times higher. If you add the bypass caps to the Adcom it sounds almost as good as the McIntosh, but not quite. But to the matter at hand, bi-wiring. It can make a large difference on many loudspeakers. In general it makes the mids and highs cleaner and more prominent sounding. This may be a bit much on some speakers, you may need some way to re-adjust the levels between the bass and the high end. The reason for the change in sound is a reduction in intermodulation distortion. See the Jon Risch stuff http://www.geocities.com/jonrisch/page7.htm ,although some of you may find it hard reading. I first heard this effect in about 1978 in a big night club set up and was at a loss to understand the differences we were hearing. Due to the loss of one conductor in a four conducor cable that ran under a dance floor we had to go from a bi-wire set up back to a uno-wire set up. The sound was distorted in a very subtle way. People were arguing over whether to re-cone the dual 15s in the speaker, or re-diaphragm the 2" throat midrange, or both. Replacing the bad wire and restoring the system to bi-wire status solved the problem. This was very hard to understand, and even harder to believe, even though we all could hear it. The strangest part of this story is that this system was bi-wired by accident rather than design. In 1978 bi-amping was common in large systems, but bi-wiring was something as yet in the future. I can't remember when I first saw speakers set up from the factory with bi-wire inputs, but it was years later than this.

[djk]

"Can you explain the 47uF cap? A special type? Where in the PS? Sounds interesting. I have Macs..." Most McIntosh run on +/- 40V or so.Just put one on each rail.Observe polarity or use a non-polar cap.If you own a MC2300 it is dual mono so you would need four pieces to do it.While you have the bottom off I also recommend tacking 0.1µF bypass caps across all the elecrolytics in the signal path, there are usually four in each channel (consult your SM).I also cut off all the 1/4" push-on connectors at the speaker relay, bridge rectifier, and filter caps.Clean the relay contacts with #600 emory and use Cramolin.On plug in driver boards suck all the solder off the pins and re-solder with 4% silver solder, then Cramolin.Pay close attention to the input sensitivity switch on the back panel, there are series elecrolytic capacitors on it as well as dirty contacts.